Spindle oscillator



NOV. 7, 1939. L 2,178,850

' SPINDLE OSCILLATOR Filed Dec. 6, 1937 2 Sheets-Sheet 1 JL/b: 7 Z

INVENTOR. A L5 5/? TH DAL L BY I ATTORNEY.

Patented Nov. 7, 1939 ATENT, OFFIQE SPINDLE OSCILLATOR Albert H. Dall,Silverton, Ohio, assignor to Cin cinnati Grinders Incorporated,Cincinnati, Ohio, a corporation of Ohio Application December 6, 1937,Serial No. 178,286

9 Claims. (Cl. 121-157) This invention relates to grinding machines andmore particularly to improve means for effecting oscillation of thegrinding wheel spindle of such machines for the purpose of eliminating.5 grinding lines from the work.

One of the objects of this invention is to provide a mechanism for thepurpose described which will have a smooth reversal, thereby eliminatingany shock or undesirable vibration which will impair the finish on thework.

Another object of this invention is to provide a mechanism of thecharacter described which is positive in action and therefore will notstall at the reversing points.

A further object of this invention is to provide improved controlmechanisms for starting and stopping the device, and for varying thelength and time of a stroke, said last named mechanism being adjustableduring operation of the device.

Other objects and advantages'of the present invention should be readilyapparent by reference to the following specification considered inconjunction with the accompanying drawings illustrative of oneembodiment thereof, but it will be understood that any modifications maybe made in the specific structural details within the scope of theappended claims without departing from or exceeding the spirit of theinvention.

Referring to the drawings in which like reference numerals indicate likeor similar parts:

Figure l is a section through the spindle of a grinding machine showingthe application of the reciprocating mechanism thereto,

Figure 2 is a section on the line 2-2 of Figure 1.

Figure 3 is a plan view of the top of the mechanism shown in Figure 2.

Figure 4 is a section on the line 4-4 of Figure 2. i

Figure 5 is a diagrammatic view of the hydraulic control circuit.

Figure 6 is a detail section on the line 66 of Figure 2.

Referring to Figure l of the drawings, the reference numeral ll]indicates the spindle of, a grinding machine, said spindle beingsupported for rotation in bearings H and i2 carriedby the main support53 of the machine. It will be noted that the bearings are straightwhereby the spindle may be axially reciprocated relative thereto.

A conventional driving pulley I4 is secured to one end of the spindlefor efiecting power rotation thereof, and a grinding wheel I5 is securedto the other end by suitable conventional clamping means.

This invention deals with a mechanism for effecting a limited amount ofreciprocation oi the spindle during rotation of the'grinding wheel, forthe purpose of removing grinding marks or lines from the work to improvethe finish thereof. To 5 this end the spindle is provided with anannular rib H; which is antifrictionally embraced by a surroundingsleeve ll, the sleeve in turn being pivotally connected at diametricallyopposite points ll, as shown in Figure 2, to an operating 10 lever I 8.This lever has a ball shaped end I9 by which it is supported for pivotalmovement between the cup. shaped ends of locating members 20. This balland socket connection serves as a pivot point for oscillation of thelever. The 15 sleeve thus serves as a motion transmitting connectionbetween the oscillating lever and the rotating spindle for efiectingoscillation of the spindle.

The other end of the lever has a ball and sock- 20 et connection 2| withthe central portion of a piston 22 which is reciprocably mounted in-acylinder 23. It will now be obvious that by introducing fluid underpressure into one end of cylinder 23 and connecting the other end to ex-25 haust, that the lever l8 may be power moved to thereby causereciprocation of the grinding wheel.

A control mechanism has been provided for governing the admittance andexhaust of fluid to cylinder 23 in such a manner that reversal 3 thereofmay be efiected in a very smooth and efficient manner so that noundesirable shock or vibration will be created which will impair thefinish which it is desired to produce on the work. This reversal isefiected by a member moving at 35 a rate independent of the rate of theother moving parts, whereby a definite period of time may be providedfor reducing the pressure in one end of cylinder 23 and increasing thepressure in the other end to provide, first, an equalized pressure 0 inboth ends to stop the movement of the piston, and then a further andcontinued inverse pressure change to ultimately effect movement in a newdirection. The movement of the reversing member is initiated by a pilotvalve, and there- 45 after it is independent of the pilot valve in thatthe movement will continue regardless of whether the pilot valve shouldstop moving or not.

Referring to Figure 5, the reversing valve consists of an axiallymovable sleeve 24 which has a 50 central annular groove 25 which isalways in communication with an exhaust line 26. This sleeve also has apair of annular grooves 26' and 27 which are always in communicationwith pressure ports 28 and 29 respectively. These ports 55 are connectedby a channel to a suitable source of pressure, such as a pump 3|, whichhas an intake 32 through which fluid is withdrawn from a suitablylocated reservoir 33. For protective purposes an overload relief valve34 may be connected to the channel 30. The rate of movement orreciprocation of the grinding wheel may be controlled by providing athrottle valve 35 in the channel 3i: to thereby vary the rate of fluiddelivered per unit of time to the cylinder.

The opposite ends of the cylinder 23 are connected by channels 38 and 31to ports 39 and 38 formed in the valve housing 40 and located betweenthe exhaust groove 25 and the pressure ports 23 and 29. It will now beapparent that when the sleeve is at one end of its stroke, that thepressure groove 26 is connected to the port 38, and that the port 39 isconnected to the exhaust groove 25 whereby the piston 22 will movetoward the left, and when the sleeve 24 is shifted to the other end ofits stroke that the port 39 will be connected to the pressure groove 21and port 38 will be connected to exhaust groove 25 whereby piston 22will move toward the right as viewed in Figure 5.

The sleeve 24 is constrained to move at a relatively moderate rate ascompared to the high speed shifting effected by load and fire mechanismsusually employed in machine tools for effecting reversal of movingparts. Load and fire mechanisms depend upon the controlled part fortheir actuation, while in the present instance, once the movement isstarted, it will continue regardless of whether the controlled partshould stop or not. The result is that it is practically impossible forthe mechanism to stall during operation.

The above result is obtained by providing'a pilot valve controlmechanism for the reversing valve comprising a plunger 4|, which issupported for reciprocation in opposite ends of the housing 40, forcontrolling the time of starting of the shifting movement of thereversing valve sleeve. This plunger has a central spool 42, and endspools 43 and 44, the end spools being smaller in diameter than thecentral spool thereby providing difierential areas between opposingfaces of the spools. The spool 42 moves relative to the exhaust port 25for the purpose of closing the same, and the spools 43 and 44 moverelative to pressure ports 45 and. 46 respectively for the purpose ofalternately opening the same to cause admission of pressure to theannular grooves 41 and 48 formed in the plunger 4|.

The plunger 4| is always at the opposite end of its stroke to what thesleeve 24 is, at the beginning of a cycle. In other words, if theplunger 4| is all the way to the left, the sleeve 24 is all the way tothe right. In Figure 5, the plunger 4| is shown in a central position orhalf way through a given stroke and it will be noted that the piston 22is also shown as having moved half way through its stroke.

Since the sleeve 24 is in its right hand position, the plunger 4| musthave started from its left hand extreme position. In that position, theannular groove 41 communicates with port 45, whereby pressure fluid actson the left end of the sleeve 24, to shift the same into its right handposition, and on the differential areas of the spools 42 and 43,creating a resultant force on the plunger 4| in 'a right hand direction.This force urges the plunger into contact with the end of a lever 52,which is pivotally mounted ona' pin 53 carried by an adjustablesupporting block 54. The other end of the lever engages a plunger 5|,shown in Figure 1, which in turn abuts the side of the lever l8. It willbe remembered that the lever I8 is moved by the piston 22, and since thepiston 22 is traveling toward the left, it permits clockwise rotation ofthe lever 52 under the urge of the resultant of the hydraulic pressureacting on the opposing ends of the differential spools 43 and 42.

A second lever 55 is pivotally mounted at the opposite end of plunger 4|on a pin 56 carried The lower end of by an adjustable block 51. thislever engages a plunger which in turn abuts the opposite side of leverl8. As the lever |8 moves toward the left under the urge of piston 22,it causes clockwise rotation of the lever 55. It is through the twolevers 52 and 55, that motion is transmitted from the piston 22 to theplunger 4|. During the first part of the stroke of the plunger 4| it ishydraulically urged against one of these levers to follow the movementof the piston 22. After it reaches a position where the spool 43 closesthe pressure port 45 or, when moving in the opposite direction, when thespool 44 closes the pressure port 46, the value of the differentialhydraulic urge decreases to a point where the plunger will no longerfollow the lever. Thereafter it must be positively moved by the otherlever.

As the plunger 4| continues its movement toward the right from theposition shown in Figure 5, the spool 42 closes the port 56 and therebyseals the annular groove 48 from the exhaust line 26 whereby a closedchamber is formed. Upon further movement, the pressure port 45 isuncovered by the spool 44 and the port 56 is connected to the annulargroove 41. The result of this is that the pressure rises in the groove48 and falls in the groove 41 and a suificient resultant is built up tocause movement of the sleeve 24 toward the left. It will be noted thatmovement of the sleeve 24 to the left will effect further opening of theexhaust port 56 thereby causing a further drop in the pressure inannular groove 41 so that a greater pressure differential is createdbetween the ends of the sleeve which will accelerate the movement. Inother words, the further the sleeve moves, the more the exhaust port isopened and even if the plunger 4| should stop its movement. As thesleeve moves toward the left, it closes the motor ports 38 and 39whereby the pressure drops in the right hand end of cylinder 23 andrises in the left hand end. This causes deceleration of the piston 22 sothat a smooth reversal may be effected without shock. It will be notedthat this is accomplished during that part of the movement of sleeve 24which is the slower. As the sleeve continues its movement at a morerapid rate, it connects motor port 39 to the pressure groove 21 and themotor port 38 to the exhaust groove 25. This will result in a more rapidrate of change of pressure in the opposite ends of the cylinder 23. Itwill thus be noted that the inverse change in pressure in opposite endsof cylinder 23 is effected at a constantly increasing rate of change.

Means have been provided for changing the stroke of the piston'22 andthereby the amount of the' lateral movement of the-wheel I5. This isaccomplished by varying the amount of lost motion between the levers 52,and the plunger 4|. As previously mentioned, the lever 52 is pivotallymounted on'an adjustable block 54 and this block is guided by a plunger58 which is slidably mounted in a bore 59 formed in the casting 6B. Asshown in Figures 4 andfi, the plunger 58 has an annular groovetl formedtherein for receiving an eccentric pin 62 formed integral with therotatable shaft 63. This shaft projects through the top of the castingand is provided with an operating handle 54 which has a spring pressedplunger 65 in the end thereof. As shown in Figure 3, the. lever 64 movesrelative to an indicator plate 65 in which is formed a series of smallholes 57 for receiving the end of the plunger 65. To vary the stroke,the operator lifts on the plunger 65 and rotates the lever 65 and thenreleases the plunger. The result of this is that the eccentric pin 62shifts the plunger 58 and thereby the fulcrum of lever 52.

It will be noted from Figure 1 that if the pivot pin 53 for the lever 52is moved toward the right, that the lever l8 will move througha greaterarc before it picks up the lever 52 and rotates it. For stopping thedevice the lever 55 is also mounted on an adjustable fulcrum aspreviously mentioned and as shown in Figure 6, the block is providedwith an integral guiding plunger 68 which slides in a bore 69 providedin the casting 60.

Plunger 68 is provided with an annular groove TB into which fits aneccentric pin 1! integral with the end of. a rotatable shaft 12. Thisshaft projects through the top of the casting 60 and is provided with anoperating handle 13. As shown in Figure 3, the handle 13 moves relativeto an indicator plate 14 and has two positions, one of which isindicated at off and the other at on. When the lever is moved to the offposition, the fulcrum 56 for the lever 55 is shifted a sufficientdistance to the left that the lever l8 will not shift the plunger 4! asufficient distance to open the pressure port 46. Whereupon the piston22 will stop when it hits the end of cylinder 23 and be held againstthat end of the cylinder by hydraulic pressure. It should also be notedthat this means that the wheel will always be stopped in the sameposition laterally.-

There has thus beenprovided an improved mechanism for the purposesdescribed comprising a telescoping pilot and reversing valve with motiontransmitting connections from the actuated part to the pilot valve,together with means for varying the amount of lost motion in thoseconnections for varying the length of the stroke,

'and additional means for rendering one of the motion transmittingconnections ineifective for stopping purposes.

I claim:

1. A hydraulic oscillator for the spindle of a grinding machineincluding a lever connected to said spindle, a hydraulic pistonoperatively connected to said lever, a source of fluid pressure, andvalve means for controlling the application of fluid pressure toopposite ends of said piston including a pilot valve plunger, a sleevesurrounding said plunger, means in the sleeve for connecting said sourceof fluid pressure to opposite ends of said cylinder, multiplying linkageintervening the plunger and lever for imparting amplified movement tosaid pilot valve plunger by said lever, a fluid outlet and means in saidpilot valve plunger during movement thereof for connecting pressure toone end of said sleeve and connecting the other end of said sleeve tosaid outlet for causing sleeve movement in a direction opposite to saidplunger, said outlet connection being through said sleeve wherebymovement of the sleeve will movement.

2; In a spindle reciprocating mechanism of the class described, thecombination of a spindle, a piston operatively connected with saidspindle for effecting its reciprocation, a hydraulicpressure sourceincluding a hydraulic medium, a conduit for the medium, .a secondconduitproviding a discharge outlet, a reversing valve for connectingsaid conduits to create pressure differentials on said piston causingopposite movements thereof, a pilot valve, means connecting saidconduits for creating a pressure diiferential on both of said valves,motion transmitting 3 connections whereby the pilot valve is caused tofollow up the movement of said piston under the urge of said pressuredifferential, means responsive to movement of the pilot valve forinversely changing the pressure differential on both of said valveswhereby the reversing valve will move in a direction to inversely changethe pressure differential on said'piston, and means in the reversingvalve for increasing the rate of change of the pressure differential onitself in a direction to increase its rate of movement and therebyincrease the rate of change in the pressure differential on said pistonto effect reversal of the latter.

3. In a spindle reciprocating mechanism of the class described, thecombination of a spindle, a piston operatively connected forreciprocation of the spindle, a source of fluid pressure having adelivery conduit, a second conduit providing a discharge outlet, areversing valve for connecting said conduits tocreate opposite pressuredifferentials on said piston and thereby movement in oppositedirections, a pilot valve, means connecting said pressure to one end ofbothof said valves thereby holding the reversing valve in one extremeposition to cause a definite direction of movement of said piston,motion transmitting connections whereby the pilot valve is caused tofollow up the movement of said piston under the urge of said pressure,means responsive to a partial movement of said pilot valve fordisconnecting the pressure source from one end of both of said valvesand impounding the fluid, means responsive to the final movement of saidpilot valve for connecting said pressure source to the other end of saidvalve will start to move, means on the reversing valve for releasing theimpounded fluid at a gradually increasing rate and thereby equalizeaccelerate its own valves whereby the reversing the pressure on saidpiston whereby the piston.

and pilot valve will stop moving but the reversing valve will continueits movement, continued movement of. the reversing valve increasing thepressure differential thereon whereby its own movement will beaccelerated and thereby effect an accelerated change in the pressuredifferential on said piston to effect reversal thereof.

4. In a spindle reciprocating mechanism of the class described, thecombination of a spindle, a piston operatively connected with saidspindle for effecting reciprocation thereof, a source of fluid pressureincluding a delivery conduit, a second conduit providing a dischargeoutlet, a reversing .valve having a first position for connecting themeans responsive valve to follow the movement of the piston, meansresponsive to movement of thepilot valve for closing said pressureconnection and nullifying said hydraulic urge whereby the piston willpositively cause movement of. the pilot valve, and to further movementof the pilot valve for connecting pressure to the other end of saidvalves to cause shifting of the reversing valve. p

5. In a spindle reciprocating mechanism of the class described, thecombination of a spindle, a piston operatively connected with saidspindle for effecting its reciprocation, a source of fluid pressureincluding a delivery conduit, a second conduit providing a dischargeoutlet, a reversing valve for connecting said conduits to create apressure differential on said piston and thus cause movement thereof, apilot valve, means connecting said conduits for creating a pressuredifferential on both of said valves, a first motion transmittingconnection between the pilot valve and piston whereby the pilot valve iscaused to follow the movement of the piston under the urge of thepressure thereon, means responsive to movement of the pilotvalve forequalizing the pressure on opposite ends of said valve whereby the pilotvalve will stop, a second motion transmitting connection from the pistonfor positively continuing the movement of the pilot valve, meansresponsive to further movement of the pilot valve for creating aninverse pressure differential on said valves to effect movement of thereversing valve, means responsive to movement of the reversing valve foraccelerating its own movement to increase the rate of pressuredifferential change on said piston to effect reversal thereof.

6. In a spindle reciprocating mechanism of the class described, thecombination of a spindle, a piston operatively connected with saidspindle for effecting reciprocation thereof, a source of fluid pressureincluding a delivery conduit, a second conduit providing a dischargeoutlet, a reversing valve for connecting said conduits to said piston ina manner to cause movement thereof, a pilot control valve for saidreversing valve, levers interposed between each end of the pilot valveand actuable by said piston, hydraulic means for causing the pilot valveto follow the movement of the piston during one half of its stroke, saidlevers positively moving mainder of its stroke, and means for adjustingthe amount of lost motion between said levers and pilot valve to varythe length of stroke of said piston.

7. In a spindle reciprocating mechanism of the class described, thecombination of a spindle, a piston operatively connected with saidspindle for effecting its reciprocation, a hydraulic pressure sourceincluding a delivery conduit, a second conduit, a reversing valve fordetermining the connections of said conduits to'said piston foreffecting opposite movement thereof, apilot valve, fluid pressure meanscontrolled by said pilot valve for causing shifting of said reversingvalve, levers pivotally mounted between said pilot valve and piston,each lever having one end adjacent said pilot valve and the other endadjacent a portion the pilot valve the reactuable by said piston wherebythe pilot valve and piston will move in opposite directions, fluidpressure means for causingthe pilot valve to follow the movement of thepiston during the first half of its stroke, said lever connectionscausing positive movement of the plot valve through the remainder of itsstroke, and means to render one of said levers ineffective whereby thepiston will complete its stroke without completing the shirting movementof said pilot valve.

8. In a spindle reciprocating mechanism of the class described, thecombination of a spindle, a piston operatively connected with saidspindle for efiecting its reciprocation, a hydraulic pressure sourceincluding a delivery conduit, a second conduit, a reversing valve fordetermining the connections of said conduits to said piston foreffecting opposite movement thereof, a pilot valve, fluid pressure meanscontrolled by said pilot valve for causing shifting of said reversingvalve, levers pivotally mounted between said pilot valve and piston,each lever having one end adjacent said pilot valve and the other endadjacent a portion actuable by said piston whereby the pilot valve andpiston will move in opposite directions, fluid pressure means forcausing the pilot valve to follow the movement of the piston during thefirst half of its stroke, said lever connections causing positivemovement of the pilot valve through the remainder of its stroke, meansto render one of said levers ineficective whereby the piston willcomplete its stroke without completing the shifting movement of saidpilot valve, and means for adjusting the other of said levers to varythe amount of lost motion between the lever and pilot valve to therebyvary the stroke of said piston.

9. In a spindle reciprocating mechanism of the class described, thecombination of a spindle, a

piston operatively connected with said spindle for effecting itsreciprocation, a hydraulic pressure source including a delivery conduit,a second conduit, a reversing valve for determining the connections ofsaid conduits to said piston for effecting opposite movement thereof, apilot valve. fluid pressure means controlled by said pilot valve forcausing "shifting of said reversing valve, levers pivotally mountedbetween said pilot valve and piston, each lever having one end adjacentsaid pilot valve and the other end adjacent a portion actuable by saidpiston whereby the pilot valve and piston will move in oppositedirections, fluid pressure means for causing the pilot valve tofollowthe movement of the piston during the first half of its stroke, saidlever connections causing positive movement of the pilot valve throughthe remainder of its stroke, means to render one of said leversinefiective whereby the piston will complete its stroke withoutcompleting the shifting movement of said pilot valve, means foradjustingthe other of said levers to vary the amount of lost motion between thelever and pilot valve to thereby vary the stroke of said piston, and athrottle valve located in said conduit for varying the rate'ofoperationof said piston.

ALBERT I-I. DALL.

